"When one person buys an Apple product, it makes the experience for other Apple customers better by supporting the developer econystem. This network effect attracts a stable and growing user base. TSLA is unlikely to sustain a competitive advantage by having a network of charging stations or by accumulating driver data."

"Competition was very slow to develop for Apple ... By contrast, every major car company in the world intends to compete with TSLA in electirc vehicles."

"Steve Jobs attracted and retained a senior team of loyal lieutenants who implemented his vision ... Mr. Musk is a one-man show (and one distracted with many ventures at that)."

Greenlight is long GM, meanwhile, and sees the car companies as opposites.

"GM is capitalized to survive any foreseeable downturn," citing bllions of dollars in free cash flow, among other reasons. Meanwhile, Tesla "is capitalized to surivve only the next three quarters."

"GM bears are focused on the overhang from leased vehicles returning to the market ... Tesla faces the same risk and then some. 2014 was the first year of Tesla's three-year leasing program. Already, many of those cars are hitting the resale market at suprisingly low prices."

Performance has waned for Greenlight recently, however. The firm's funds dropped 2.8% net of fees through the end of the second quarter this year, compared to a 9.3% return in the S&P 500 index, according to its letter.